Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

Abstract

Abstract. Increases in temperature and grazing intensity are believed to promote the relative abundance of C 4 plants in grassland communities in Inner Mongolia. However, there is a lack of understanding as to which factor is the primary driver at the household scale. The relative abundance of C 4 plants in grassland communities within 32 households was monitored over a 5-year period in the typical steppe region of Inner Mongolia. The relationships between the mean annual temperature, grazing intensity and their combinations on the patterns of the relative abundance of C 4 plants across the land managed by these households were analysed. The results showed that (1) the herbage mass of the typical steppe grassland was mainly composed of C 3 plants (87%); (2) the C 4 plants were more sensitive to, and can be used as indicators of, environmental changes. These C 4 species included Cleistogenes squarrosa (Trin.) Keng, Chenopodium glaucum Linn. and Salsola collina Pall.; (3) both increasing temperature and grazing intensity promoted the relative abundance of C 4 plants. Grazing intensity was the primary driver of the change in relative abundance of C 4 plants in this region. Not only did grazing change the micro-environment of the grasslands, but also the C 3 species were preferentially grazed by the livestock. Comparison of the results with previous studies on the temporal variation in the abundance of C 4 plants suggests that the relative importance of grazing and climatic factors depends on the spatial scales of the studies, with climate being of greater importance at the regional rather than the household scale.

Applying a dryland degradation framework for rangelands: the case of Mongolia

“…In the eastern steppe, the cover of Cleistogenes squarrosa , a species that increases as grazing increases (Zhang et al. ), was higher ( P = 0.01) far from the winter shelters.…”

“…Forb cover increased far from winter shelters, as did the cover of the grazing tolerant and increaser C 4 grass Cleistogenes squarrosa (Zhang et al. ). This contrasts with the steppe and desert steppe, where forbs are more abundant close to winter shelters.…”

“…In the mountain and forest steppe and the desert steppe, we found no significant effects of ecological site or livestock use on cover of dominant species. In the eastern steppe, the cover of Cleistogenes squarrosa, a species that increases as grazing increases (Zhang et al 2014), was higher (P = 0.01) far from the winter shelters.…”

Defoliation and arbuscular mycorrhizal fungi shape plant communities in overgrazed semiarid grasslands

“…P. acaulis is generally shorter in stature (3 cm) than S. krylovii (36.5 cm) in this area and evades repeated defoliation during the growing season (Zhang et al. ). Trampling without defoliation had minimal effects on plant community composition in our study; concurring with results from other studies (Kohler et al.…”

How Willing Are Herders to Participate in Carbon Sequestration and Mitigation? An Inner Mongolian Grassland Case

“…However, the grassland in Inner Mongolia Autonomous proved to be a stable carbon sink, but the high carbon sequestration potential has not received much attention [12,13]. Since the 1980's, the land system of "double rights and one system" has been implemented in vast pastoral areas of Inner Mongolia grasslands to distribute livestock and pastures to households, making family pastures the subject of production and management [12]. As a relatively independent management unit, family pastures have independent decision-making power to grassland management.…”